In recent years, conventional analog broadcasting is being replaced by digital broadcasting in the practical use of television broadcasting.
Unlike conventional analog broadcasting, digital broadcasting has the features: that it is possible to remove the distinctions between video, audio, various items of data, and the like, and also possible to perform flexible programming; that it is possible to broadcast a large number of programs with high quality in a limited transmission bandwidth; that it is possible to provide hierarchical services in accordance with the priorities; that it is easy to upgrade a broadcast scheme per se; that it is highly interactive; and the like. In digital broadcasting a so-called MPEG (Moving Picture Experts Group)-2 moving image compression/encoding technique is used as a video encoding scheme, and an MPEG-2 system is used as a multiplexing scheme.
The standards of digital broadcasting using MPEG-2 and an MPEG-2 system are already known, and therefore will not be described in detail. Basically, broadcasters each transmit digital broadcasting in the following process. First, a broadcaster digitizes (encodes) signals of video, audio, and the like that form a program. Next, the broadcaster multiplexes the digitized signals into a signal in a form that is suitable for transmission, the form being referred to as a transport stream (hereinafter referred to as a “TS”). Then the broadcaster modulates the TS in a predetermined scheme so as to form a carrier wave, and transmits the carrier wave using one physical channel (transponder). That is, the broadcaster encodes a program into digital signals, multiplexes the digital signals, and transmits the multiplexing result as one TS on one physical channel (see FIG. 16).
Next, a description is given of a digital broadcast reception device (see Patent Document 1, for example) that receives the TS transmitted as described above. FIG. 17 is a block diagram showing an example of the structure of a conventional digital broadcast reception device. The reception device shown in FIG. 17 includes: a front end 91, to which the output of a receiving antenna 90 is input; a demultiplexer 94, to which the output of the front end 91 is input; an MPEG-2 video decoder 95 and an MPEG-2 audio decoder 96, to which the outputs of the demultiplexer 94 are input; and a data processing section 97. This digital broadcast reception device further includes a CPU 98 that controls this whole satellite digital broadcast device. The CPU 98 is connected to a memory 99.
Referring to FIG. 17, the TS received by the receiving antenna 90 is subjected to processes in the front end 91, such as the selection of a receiving transponder, demodulation, and error correction, and then is input to the demultiplexer 94. The TS, which is a stream transmitted in a multiplexing manner, is demultiplexed by the demultiplexer 94 into PSI (Program Specific Information), an MPEG-2 video ES (Elementary Stream), and an MPEG-2 audio ES, and a PS (Private Section).
The PSI acquired from the division by the demultiplexer 94 is transmitted to the CPU 98, the MPEG-2 video ES to the MPEG-2 video decoder 95, the MPEG-2 audio ES to the MPEG-2 audio decoder 96, and the PS to the data processing section 97.
The MPEG-2 video decoder 95, the MPEG-2 audio decoder 96, and the data processing section 97 appropriately process the provided MPEG-2 video ES, MPEG-2 audio ES, and PS, and output the signals obtained from the processes of the MPEG-2 video decoder 95, the MPEG-2 audio decoder 96, and the data processing section 97, to the outside of the device through a video output interface, an audio output interface, and a data output interface, which are not shown in the figures, respectively.
The CPU 98 controls the operations of the MPEG-2 video decoder 95, the MPEG-2 audio decoder 96, and the data processing section 97, while using the memory 99. The CPU 98 performs a channel selection operation based on the PSI. Here, items of the PSI are an NIT (Network Information Table), a PAT (Program Association Table), a PMT (Program Map Table), and the like. The NIT has written therein, as channel selection information about all broadcastings on a network: the frequencies of transponders, which are physical channels; the ID of a program belonging to each transponder, i.e., an SID (Service Identifier); and the like. The PAT, defined with respect to each transponder, has written therein, as channel selection information about the transponder: the SID of the program that is currently being broadcast on the transponder; and a PID (Packet Identifier) of the PMT, which is channel selection information about the SID. The PMT, defined with respect to each SID, has written therein, as channel selection information about the SID, ES information and PS information that are included in the SID. The CPU 98 sets, in the demultiplexer 94, the PIDs of the ESs and the PS that are acquired from the PMT included in the PSI, and performs channel selection by assigning the ESs and the PS to the corresponding processing devices of the MPEG-2 video decoder 95, the MPEG-2 audio decoder 96, and the data processing section 97.
As the reception device, a reception device having mounted therein two tuners is also known in recent years. This reception device can separately select different channels with the two tuners, and perform picture-in-picture simultaneous display of different programs having different materials, each created under a so-called Hi-Vision video standard.
Here, a video standard termed so-called Super Hi-Vision emerges in recent years. Super Hi-Vision is a high-definition video system having an amount of information 16 times as much as that of Hi-Vision broadcasting at the maximum, has a bit rate of approximately 24 Gbps, and therefore requires a vast amount of information of 100 to 400 Mbps even if performing compression/encoding in H.264. That is, when, as described above, a video signal is digitized to generate one TS, the amount of information included in the one TS may also increase. As a result, the amount of information to be included in one TS may be such an amount of information that cannot be completely transmitted in the frequency bandwidth (transmission capacity) assigned to each broadcaster, i.e., cannot be completely transmitted on one physical channel (see FIG. 18). That is, when broadcast in the current transmission scheme, a program created under the Super Hi-Vision standard cannot be completely transmitted on one physical channel, due to lack of transmission capacity.
In response, a technique is disclosed in which one content file is converted into a plurality of items of division distribution data and these items are transmitted on a plurality of different transmission paths (see Patent Document 2, for example). Consider the case where digital broadcasting is performed by distributing a Super Hi-Vision program into two items of division distribution data and transmitting these two items using two different physical channels. In this case, when an attempt is made to view this program with Super Hi-Vision video at the reception device end, the two physical channels are selected using two tuners, respectively, and thereby the items of division distribution data are received. In addition, the reception device requires a function of combining the received items of division distribution data and reconstructing the original Super Hi-Vision program.    Patent Document 1: Japanese Laid-Open Patent Publication No. 11-275476    Patent Document 2: International Application Published under the Patent Cooperation Treaty No. 01/056244